Rainwater Harvesting
'''Rainwater harvesting '''is the process of collecting rain water from non-permeable surfaces into barrels or cisterns for later use. History Rainwater harvesting has been used since ancient times in Southeast Asia, India, Egypt, Rome, Turkey and more. In the Philippines, the collected water was used as irrigation for rice crops1 whereas in Rome, it was used as a natural air conditioner as surrounding air cooled when the water evaporated2. All over the world, rain harvesting was common and a practical way for maintaining a water supply throughout the seasons. However, this practice was lost until recent advancements in technology such as the creation of pipelines and running water. Today once again there is a new demand for clean, sustainable water sources, especially during droughts in the Midwest. How-to Harvest Rain Commonly, rainwater is harvested from home and/or shed rooftops using the gutter system already in place, although it can work in larger scale commercial systems. These more complex systems can be built to harvest off other surfaces, to store water underground or to pump water for irrigation. At home, rain harvesting can be cheap and easy to do by buying a ready-to-use barrel or cistern and placing it at the bottom of the downspout allowing water from the roof to be collected. Simple things like a mesh filter at the top of your downspout can prevent accumulation of debris in the water barrel. A simple mathematical equation dividing the square footage of a roof by 1.6 can be used to determine how much rain your roof can collect during a 1 inch rainfall (for example, a roof with 1300 ft2/ 1.6= 800 gallons during a 1 inch rainfall)3. A spout at the bottom of a barrel can be hooked up to a hose or emptied into a watering can for easy transport. Since water is being collected from locations like roofs where other animals also reside, it can collect bacteria and other potentially harmful microorganisms. This water is considered non-potable, not drinkable4, and it is recommended to be used on flowers and lawn care instead of vegetable gardens. If some is used on vegetable gardens, do not use an overhead drip irrigation system and be sure to wash your vegetables thoroughly before consuming. Environmental Impact There are many benefits to using a rainwater harvesting system including: 1. Promotion of clean, local bodies of water. During a rainfall, pavement cannot absorb the water so the runoff continually collects pathogens, feces, oil, garbage and other waste in the streets and sidewalks. The contaminated water then travels into the sewage system or into lakes and rivers thereby polluting them and causing eutrophication. Another way to promote clean bodies of water is the installation of rain gardens . 2. Conservation of water. During heavy rainfalls, water can be collected and stored for times of dry-spells and drought which are becoming increasingly common in summers in the Midwest. Using the collected rain will not only help your garden in times of water scarcity, but will result in a reduction in your water bill. Additionally, it can help relieve drainage problems during heavy rainfalls on your property. Rules and Regulations Be sure to check out local pollution control recommendations on rainwater harvesting, because each city has unique regulations. Sources 1. Rainwater Collection. 2008. http://www.rain-barrel.net/rainwater-collection.html 2. Leung, J. (2008). Rainwater Harvesting 101. GROWNYC. http://www.grownyc.org/files/osg/RWH.how.to.pdf 3. Dahse, B. A Rainwater harvesting system for the Midwest. Geopathfinder. http://www.geopathfinder.com/RainwaterHarvestingSystem.pdf